1. Field of the Invention
This invention relates to latch assemblies for releasably maintaining movable closure elements in a desired position relative to a support therefor.
2. Background Art
Myriad designs for latch assemblies for maintaining movable closure elements in a desired position relative to a support upon which the movable closure element is mounted have been devised over the years. Different demands are placed upon these mechanisms depending upon their particular environment. However, designers of these latch assemblies universally consider and balance the following factors in their designs: 1) reliability; 2) holding capacity; 3) convenience of operation; 4) ease of manufacture; 5) ease of assembly; 6) versatility; and 7) cost. Certain of the above factors are competing in the design process and, generally, particular applications will dictate where compromises must be made. Ideally, one would optimize each of these design areas.
The agricultural and construction industries are ones in which rather severe demands are placed upon latch assemblies. Severe stresses are commonly placed on closure elements on cabs of tractors and the like. At the same time, convenience of actuation is a prime consideration, as when a hasty exit must be made from such a vehicle. This has lead to the use of squeeze-actuated assemblies of the type shown in U.S. Pat. No. 6,419,284. The squeeze actuator is integrated into a handle/bar which facilitates manipulation of the closure element as well as accessibility to the lever that is squeezed while gripping the bar to release the latch assembly to permit opening of the closure element. However, the latch assembly designs, of the type shown in U.S. Pat. No. 6,419,284, have tended towards the complicated. For example, the design shown in U.S. Pat. No. 6,419,284 uses two separate, indirect mechanisms for moving a catch element through separate internal and external actuating assemblies on the closure element. This indirect actuation requires intermediate parts which may complicate the manufacturing process and increase associated costs. Indirect mechanisms, by their nature, introduce additional parts movement that could account for a field failure.
The bars on the latch assemblies, of the type shown in U.S. Pat. No. 6,419,284, commonly have a crimped end which is bolted to the associated closure element. The particular closure element generally dictates the optimal length for the bar. Consequently, there may be a requirement to inventory complete latch assemblies with different lengths of bar to meet various demands. Manufacturing costs associated with this type of latch assembly may be increased by reason of having to offer the latch assemblies with different lengths of bar integrated thereinto. Further, if manufacturing does not proceed on an as-needed basis, inventories must be set up to anticipate demand. To avoid shortages for latch assemblies with a particular bar length, excess inventory may have to be kept on hand. This potentially adds inconvenience and expense for the purveyors of this type of latch assembly.
Another problem with the above type of latch assemblies is that it may be a difficult or complicated process to integrate components into the bars. The bars are typically tubes with internal hollows within which some of the components are situated. Ideally, components are mounted within the tubular hollows to afford a compact design, yet without requiring intricate assembly processes which increase costs. This has led to the use of separable components which engage the bars to facilitate assembly. For example, as seen in U.S. Pat. No. 6,419,284, a significant number of components are assembled through the opening which receives the actuating handle. The actuating handle itself is a separate component that must be attached to the bar and adjusted on site. A relatively large number of component assembly steps may be required to manufacture this latch assembly.
Still further, this type of latch assembly is commonly operated using cables or rods to transmit the operating force from the actuating handle to the latching mechanism. The use of intermediate rods and cables may account for a less than positive force transmission between the actuating handle and the latching structure. This type of mechanism also generally requires the capability to effect adjustments of the position of the actuating handle relative to the latching mechanism for optimal performance and to accommodate variations in the structures on which the latching assemblies are mounted. The result is that these mechanisms may become relatively expensive to manufacture, complicated, less compact and streamlined than desired, and prone to failure. Further, this type of latch mechanism may be installed so that the operator components are exposed to the operation and unsightly.
The industry is constantly seeking out latch assemblies that are improved in one or more of the areas noted above.